Occasionally, and we tend to see this in very young and very old people, that they end up developing pneumonia and they may have to be hospitalised for that.
For most people 24 to 48 hours after infection you'll see a fever, you're tired, your muscles will usually ache.It's fairly similar every time you get influenza A virus infections so most people have experienced it.
Usually within five to seven days of infection, and it's the same with pigs.They usually clear the infection, there's hardly any virus being shed by the seventh day and they're usually fully recovered by then.It's a very limited short-term infection but it can have serious consequences, both for humans and pigs, if their immune system isn't able to stop it from going down full into the lungs where they can get pneumonia.
Dr. Detmer says the pork sector is concerned about high path H5N1 Avian Influenza because humans and pigs do have the avian receptor deep in their lungs which could result in catastrophic phenomena which is why we don't want it to adapt to mammals and spread more easily.
Source : Farmscape.ca